Build system¶

Command line options for make¶

All option names must be lower case for not to override internals.

TARGET = <TARGET>

In Makefile you MUST use upper case for target value. In command line you can also use lower case.

Define default target in Makefile:

TARGET = X86

Then compile using another target:

make target=avr

MCU_<TARGET> = <MCU>

Target specific default MCU. Could be ATmega8 for AVR targets or 16F87 for 8-bit PIC targets.

Define default MCU in Makefile:

TARGET = X86
MCU_AVR = atmega328p
MCU_PIC8 = 16f84a

Then compile using another MCU:

make target=avr mcu=atmega8
make target=pic8 mcu=16f87

F_CPU = <FREQUENCY>

Generic default CPU clock speed needed by some targets like AVR and 8-bit PIC.

Define in Makefile:

F_CPU = 1000000

Then override from command line:

make f_cpu=8000000

F_CPU_<TARGET> = <FREQUENCY>: Same as F_CPU_<TARGET> but TARGET specific.

USE += ...

Add used components. Normally you want some since almost nothing is included as default.

Makefile with I2C and logging enabled:

USE += I2C LOG

Then compile by adding GPIO and using I2C in bitbang mode (which needs GPIO):

make use="gpio i2c_bitbang"

DEFINES += ...

Add defines. This basically is a shorthand for CFLAGS += -D<DEFINE>.

Usage in Makefile:

DEFINES += MY_DEFINE OTHER_DEFINE
DEFINES += MY_PI=3.1415

From command line:

make defines="CMD_DEFINE1 CMD_DEFINE2=123"